KR20180105226A - The laminate - Google Patents

Abstract

The present invention includes an organic piezoelectric material having a weight average molecular weight of 50,000 to 1,000,000 and has a normalized molecular orientation MORc of 1.0 to 15.0 when a reference thickness measured with a microwave transmission type molecular alignment meter is 50 mu m, (A) having a degree of crystallinity of 20% to 80% and an internal haze with respect to visible light of 50% or less and a peelable protective film (B) in contact with one main surface of the polymer film (A) And the maximum penetration depth hmax when the side of the film (B) in contact with the polymer film (A) is measured by the nanoindentation method is 53 nm to 100 nm.

Description

The laminate

The present invention relates to a laminate.

An organic material having piezoelectricity is known, and examples thereof include a polymer material using a helical chiral polymer having optical activity (for example, a polylactic acid-based polymer).

For example, a polymer piezoelectric substance exhibiting a piezoelectric constant of about 10 pC / N at room temperature by stretching a molded product of polylactic acid has been disclosed (see, for example, JP-A-5-152638).

It has also been reported that a highly oriented polylactic acid crystal has a high degree of piezoelectricity of 18 pC / N by a special orientation method called a forging method (see, for example, Japanese Patent Application Laid-Open No. 2005-213376 ).

However, when the polymer film is used in the production of various devices, appearance of the device (product) may be damaged due to occurrence of scratches on the polymer film, adhesion of foreign matter, and the like.

On the other hand, a protective film may be formed on the polymer film for the purpose of protecting the polymer film. Thereby, the polymer film can be stored or transported as a rolled-up roll until it is used in the production of a device, and occurrence of scratches on the polymer film at the time of handling can be suppressed.

In practice, when various devices are manufactured using a polymer film, a protective film may be peeled off immediately before the process. In this case, if the adhesion between the protective film and the polymer film is strong, a part of the protective film may remain on the surface of the polymer film.

Further, the inventors of the present invention have found that, even when the protective film can be peeled off without leaving it on the surface of the polymer film containing an organic piezoelectric material, the inventors have found that the surface of the polymer film after peeling becomes orange peel . This is because the organic piezoelectric material generally has a property of being easily deformed, and since the organic piezoelectric material is highly charged, minute foreign matter is adsorbed between the protective film and the polymer film at the time of adhesion of the protective film, Is deformed by the foreign object. In this case, the quality of the polymer film itself may be deteriorated, and further, the appearance and quality of a device manufactured using the polymer film may be deteriorated.

In view of the above circumstances, it is an object of the present invention to provide a laminate having a polymer film containing an organic piezoelectric material and a protective film, wherein the deterioration of the appearance of the polymer film after the protective film is peeled is suppressed .

Specific means for solving the problems are as follows.

<1> An organic electroluminescent device comprising an organic piezoelectric material having a weight average molecular weight of 50,000 to 1,000,000 and having a standardized molecular orientation MORc of 1.0 to 15.0 when a reference thickness measured with a microwave transmission type molecular alignment meter is 50 m, Of the polymer film (A) is 20% to 80%, and the internal haze with respect to visible light is 50%

(B) which is in contact with one main surface of the polymer film (A)

And the maximum penetration depth hmax when the side of the protective film (B) contacting the polymer film (A) is measured by the nanoindentation method is 53 nm to 100 nm.

&Lt; 2 > The laminate according to < 1 >, wherein the maximum indentation depth hmax is 53 nm to 60 nm.

(3) The protective film (B) has a base layer and an adhesive layer formed on the main surface of the base layer opposite to the polymer film (A)

Wherein the maximum indentation depth hmax is a maximum indentation depth at the time of measuring the side of the adhesive layer of the protective film (B).

&Lt; 4 > The laminate according to < 3 >, wherein the acid value of the adhesive layer is 10 mgKOH / g or less.

<5> The laminate according to <3> or <4>, wherein the substrate layer is made of a polyolefin resin or a polyethylene terephthalate resin, and the pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive.

<6> The laminate according to any one of <1> to <5>, wherein the T-shaped peel strength of the polymer film (A) and the protective film (B) is 0.07 N / 50 mm to 1 N / 50 mm.

<7> The polymer film (A) has an internal haze of not more than 40% with respect to visible light and a piezoelectric constant d ₁₄ measured by a stress-charge method at 25 ° C of not less than 1 pC / N, 6>.

&Lt; 8 > The laminate according to < 7 >, wherein the internal haze is 1% or less.

<9> The polymer film (A) according to any one of <1> to <8>, wherein the normalized molecular orientation MORc is 3.5 to 15.0 and the product of the normalized molecular orientation MORc and the crystallinity is 70 to 700. sieve.

<10> The laminate according to any one of <1> to <9>, wherein the organic piezoelectric material is a helical chiral polymer (X) having optical activity.

<11> The laminate according to <10>, wherein the helical chiral polymer (X) is a polylactic acid-based polymer having a main chain containing a repeating unit represented by the following formula (1).

<12> The laminate according to <10> or <11>, wherein the helical chiral polymer (X) has an optical purity of 95.00% ee or more.

<13> The laminate according to any one of <10> to <12>, wherein the content of the helical chiral polymer (X) in the polymer film (A) is 80 mass% or more.

(14) The polymer film (A) as described in any one of (1) to (10), wherein the polymer film (A) contains at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group and an isocyanate group and has a weight average molecular weight of 200 to 60000 (10) to (13), wherein at least one stabilizer (Y) selected from the group consisting of a stabilizer (Y2) having a hydroxyl group and a hydroxyl group is contained in an amount of 0.01 part by mass to 10 parts by mass with respect to 100 parts by mass of the helical chiral polymer &Lt; / RTI >

(15) The elastic film of the protective film (B) and the elastic film of the polymer film (A) satisfy the following relational expression (F):

The elastic modulus of the protective film (B) / the elastic modulus of the polymer film (A) (Formula F)

The laminate according to any one of < 1 > to < 14 >

According to the present invention, there is provided a laminate having a polymer film including a helical chiral polymer and a protective film, wherein the polymer film after peeling off the protective film is prevented from deteriorating in appearance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a first embodiment of a laminate according to the present disclosure; FIG.
2 is a cross-sectional view showing a second embodiment of the laminate according to the present disclosure.

Hereinafter, an embodiment of the present invention will be described.

In the present specification, the numerical range indicated by using &quot; to &quot; means a range including numerical values before and after &quot; to &quot; as a lower limit value and an upper limit value.

In the present specification, the term &quot; polymer film &quot; is a concept including a polymer sheet.

In the present specification, the main surface of the film means a surface facing the thickness direction of the film (in other words, a surface including the longitudinal direction and the width direction). Also, the &quot; main surface &quot; may be simply referred to as &quot; surface &quot;.

In this specification, &quot; face &quot; of a member means &quot; main face &quot; of the member unless otherwise specified.

In the present specification, the term "MD direction" is a machine direction, that is, a stretching direction, and the term "TD direction" is a direction transverse to the MD direction and parallel to the main surface of the film.

«Laminate»

The laminate according to the present disclosure includes an organic piezoelectric material having an optically active weight average molecular weight of 50,000 to 1,000,000 and has a normalized molecular orientation MORc of 1.0 占 퐉 when a reference thickness measured with a microwave transmission type molecular alignment meter is 50 占 퐉, To 15.0, a degree of crystallinity obtained by the DSC method is 20% to 80%, and an internal haze with respect to visible light is 50%

(B) which is in contact with one principal surface of the polymer film (A)

The maximum indentation depth hmax when the side of the protective film (B) in contact with the polymer film (A) is measured by the nanoindentation method is 53 nm to 100 nm.

Further, the laminate according to the present disclosure may further include another peelable protective film in contact with the other main surface of the polymer film (A).

The present inventors have found that when a protective film is peeled from a laminate in a laminate having a polymer film containing an organic piezoelectric material and a peelable protective film, a part of the protective film tends to remain on the surface of the polymer film, Further, even when the protective film is not left on the surface of the polymer film, it has been found that the surface of the polymer film tends to become orange peel texture.

Here, &quot; orange fill &quot; means that the surface of the citron has wrinkles or irregularities (steps) as in the citron peel. The width of each concave portion of the orange fill is about several millimeters, and the depth is about several mu m to several tens of mu m.

Thus, the present inventors have employed a laminate having a layered structure in which a polymer film (A) containing the organic piezoelectric material and having the aforementioned characteristics is combined with a protective film (B), and further, a protective film B) of the side contacting the polymer film (A) was measured by the nanoindentation method, the maximum indentation depth hmax was adjusted to the above range. Thus, it was found that deterioration of the appearance of the polymer film (A) after peeling the protective film (B) can be suppressed, and the present invention was accomplished.

In the present disclosure, when the maximum penetration depth hmax is 53 nm or more, a part of the protective film (B) remains on the surface of the polymer film (A) after peeling off the protective film (B) Is prevented from being orange peeled.

Further, when the maximum penetration depth hmax is 100 nm or less, the protective film (B) can be easily peeled from the laminate. That is, the peelability of the protective film (B) is improved.

Therefore, by setting the maximum indentation depth hmax within the above range, deterioration of the appearance of the polymer film (A) after the protective film (B) is peeled is suppressed.

Preferred embodiments of the laminate according to the present disclosure will be described below.

In the present disclosure, the organic piezoelectric material may be a helical chiral polymer (hereinafter sometimes referred to as a helical chiral polymer (X)), or may be an organic piezoelectric material other than a helical chiral polymer.

In the laminate according to the present disclosure, it is preferable that the maximum indentation depth hmax is 53 nm to 60 nm.

As described above, when the maximum penetration depth hmax is 53 nm or more, the surface of the polymer film (A) is prevented from becoming orange peel after peeling off the protective film (B).

If the maximum indentation depth hmax is 60 nm or less, a part of the protective film (B) can be prevented from remaining on the surface of the polymer film (A), and the peelability of the protective film (B) is further improved.

Therefore, by setting the maximum indentation depth hmax within the above range, deterioration of the appearance of the polymer film (A) after the protective film (B) is peeled is further suppressed.

In the laminate according to the present disclosure, the protective film (B) has a base layer and an adhesive layer formed on the main surface of the base layer opposite to the polymer film (A)

It is preferable that the maximum indentation depth hmax is a maximum indentation depth when the side of the adhesive layer of the protective film (B) is measured.

As a result, since the protective film (B) and the polymer film (A) are adhered via the adhesive layer, the adhesive strength between the two films becomes high.

When the maximum penetration depth hmax of the protective film B, that is, the maximum penetration depth hmax of the adhesive layer is 53 nm or more, a part of the adhesive layer remains on the surface of the polymer film A after peeling off the protective film (B) And the surface of the polymer film (A) are inhibited from being orange peel.

Further, when the maximum penetration depth hmax is 100 nm or less, the protective film (B) can be easily peeled from the laminate. That is, the peelability of the protective film (B) is improved.

In the laminate according to the present disclosure, the acid value of the adhesive layer is preferably 10 mgKOH / g or less.

As a result, the decrease in the molecular weight of the organic piezoelectric material, for example, the helix chiral polymer (X) contained in the polymer film (A) is suppressed, and the stability of the polymer film (A) is improved.

In the laminate according to the present disclosure, it is preferable that the base layer is made of a polyolefin resin or a polyethylene terephthalate resin, and the pressure-sensitive adhesive layer includes an acrylic pressure-sensitive adhesive.

As a result, the adhesive strength between the base layer and the adhesive layer becomes high, so that the protective film (B) can be easily peeled from the laminate.

In the laminate according to the present disclosure, the T-shaped peel strength of the polymer film (A) and the protective film (B) is preferably 0.07 N / 50 mm to 1 N / 50 mm.

When the T-shaped peel strength is 0.07 N / 50 mm or more, the adhesive strength between the polymer film (A) and the protective film (B) is secured.

When the T-type peel strength is 1 N / 50 mm or less, the peelability of the protective film (B) is secured.

In the laminate according to the present disclosure, the polymer film (A) has an internal haze of not more than 40% with respect to visible light and a piezoelectric constant d ₁₄ measured at 25 캜 by a stress-charge method of not less than 1 pC / N .

The polymer film (A) is a piezoelectric film having transparency. Thereby, the polymer film (A) can be applied to various piezoelectric devices.

In the laminate according to the present disclosure, from the viewpoint of improving the transparency of the polymer film (A), the internal haze is preferably 1% or less.

In the laminate according to the present disclosure, it is preferable that the polymer film (A) has a normalized molecular orientation MORc of 3.5 to 15.0, and a product of the normalized molecular orientation MORc and the crystallinity of 70 to 700. [

The polymer film (A) is a piezoelectric film.

Therefore, when the normalized molecular orientation MORc is in the above range and the product is in the above range, the piezoelectric film of the polymer film (A) improves.

When the polymer film (A) is used as a piezoelectric film, the helical chiral polymer (X) in the laminate according to the present disclosure contains a repeating unit represented by the following formula (1) from the viewpoint of further improving piezoelectricity Is a polylactic acid-based polymer having a backbone chain.

When the polymer film (A) is used as a piezoelectric film in the laminate according to the present disclosure, the optical purity is preferably 95.00% ee or more from the viewpoint of further improving piezoelectricity.

In the laminate according to the present disclosure, the content of the organic piezoelectric material in the polymer film (A) is preferably 80 mass% or more. For example, when the organic piezoelectric material is a helical chiral polymer (X), the content of the helical chiral polymer (X) in the polymer film (A) is preferably 80 mass% or more.

In the laminate according to the present disclosure, the polymer film (A) preferably contains at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group and an isocyanate group, from the viewpoint of improving the heat and humidity resistance of the polymer film (A) (Y) selected from the group consisting of a stabilizer (Y1) having a weight average molecular weight of 200 to 60000 and a stabilizer (Y2) having an imino ether group is added to 100 parts by mass of the organic piezoelectric material Is preferably 0.01 part by mass to 10 parts by mass. For example, when the organic piezoelectric material is a helical chiral polymer (X), a stabilizer (Y1) having a weight average molecular weight of 200 to 60000 having at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group and an isocyanate group ) And at least one stabilizer (Y2) having an imino ether group in an amount of 0.01 to 10 parts by mass based on 100 parts by mass of the above-mentioned helix chiral polymer (X) .

Hereinafter, the laminate according to the present disclosure will be described in more detail.

&Lt; Polymer film (A) >

[Organic piezoelectric material]

The organic piezoelectric material contains an organic piezoelectric material having a weight average molecular weight of 50,000 to 1,000,000.

The organic piezoelectric material in the present disclosure can be employed regardless of a low-molecular material or a high-molecular material, and examples thereof include polyvinylidene fluoride or polyvinylidene fluoride copolymer, polyvinylidene cyanide or cyanide vinylidene copolymer , Nylon 9 and nylon 11, aromatic nylon, alicyclic nylon, polyurea and polylactic acid, polyhydroxycarboxylic acids such as polyhydroxybutyrate, cellulose derivatives, polypeptides and the like .

From the viewpoints of good piezoelectric properties, processability, availability and the like, it is preferable to use an organic piezoelectric material of a polymer, particularly a helix chiral polymer (X) having optical activity.

- Helical chiral polymer (X) -

When the polymer film (A) in the present disclosure contains a helical chiral polymer, the helical chiral polymer is a helical chiral polymer having a weight average molecular weight of 50,000 to 1,000,000 and an optical activity (in the present specification, Also referred to as chiral polymer (X)).

Here, the &quot; helical chiral polymer having optical activity &quot; refers to a polymer having a molecular structure having a spiral structure and having a molecular optical activity.

The helical chiral polymer (X) in the present disclosure is a polymer having a weight average molecular weight of 50,000 to 1,000,000 among the above-mentioned &quot; optically active helix chiral polymer &quot;.

Examples of the helical chiral polymer (X) include a polylactic acid-based polymer and poly (beta -hydroxybutyric acid).

The optical purity of the helix chiral polymer (X) is preferably 95.00% ee or more, more preferably 96.00% ee or more, further preferably 99.00% ee or more, and still more preferably 99.99% ee or more. It is preferably 100.00% ee.

By setting the optical purity of the helical chiral polymer (X) within the above range, crystallinity and packing property of the polymer crystal in the polymer film (A) are enhanced. As a result, for example, when the polymer film (A) is used as a piezoelectric film, the piezoelectricity (piezoelectric constant) can be further improved.

Here, the optical purity of the helical chiral polymer (X) is a value calculated by the following formula.

Optical purity (% ee) = 100 x | L body weight-D body weight | / (L body weight + D body weight)

That is, the optical purity of the helical chiral polymer (X)

(Absolute value) of the amount of the L-form of the helical chiral polymer (X) [mass%] and the amount of the D form of the helical chiral polymer (X) (Sum) of the amount [mass%] of the helix chiral polymer (X) and the amount [amount of mass%] of the helix chiral polymer (X) "is a value obtained by multiplying" 100 "

The amount [mass%] of the L-form of the helical chiral polymer X and the amount [mass%] of the D-form of the helix chiral polymer X are determined by a method using a high-performance liquid chromatography use. The measurement method is as follows.

A 1.0 g sample (polymer film (A)) was weighed into a 50 mL Erlenmeyer flask, and 2.5 mL of IPA (isopropyl alcohol) and 5 mL of 5.0 mol / L sodium hydroxide solution were added. Subsequently, the Erlenmeyer flask containing the sample solution is placed in a water bath at 40 DEG C and stirred for about 5 hours until the helical chiral polymer (X) is completely hydrolyzed.

After the sample solution is cooled to room temperature, it is neutralized by adding 20 mL of a 1.0 mol / L hydrochloric acid solution, and the Erlenmeyer flask is tightly mixed. Add 1.0 mL of the sample solution into a 25 mL volumetric flask, and prepare 25 mL of the mobile phase as the HPLC sample solution 1. 5 μL of the HPLC sample solution 1 is injected into the HPLC apparatus, and the D / L body peak area of the helical chiral polymer (X) is determined under the following HPLC conditions to calculate the amount of the L-form and the amount of the D-form.

-HPLC measurement conditions -

ㆍ Column

Optical split column, SUMICHIRAL OA5000 manufactured by Sumika Center Co., Ltd.

ㆍ Measuring device

Liquid chromatography, manufactured by Nippon Bunko Co.,

ㆍ Column temperature

25 ℃

ㆍ Mobile phase

1.0 mM-copper sulfate (II) buffer / IPA = 98/2 (V / V)

Copper sulfate (II) / IPA / water = 156.4 mg / 20 mL / 980 mL

ㆍ Mobile flow rate

1.0 ml / min

ㆍ Detector

UV detector (UV 254nm)

As the above-mentioned helical chiral polymer (X), a compound having a main chain containing a repeating unit represented by the following formula (1) is preferable from the viewpoint of further improving the piezoelectricity when the polymer film (A) is used as a piezoelectric film.

Among the compounds having a repeating unit represented by the above formula (1) as a main chain, a polylactic acid-based polymer is preferable.

Here, the polylactic acid polymer refers to a polylactic acid (a polymer comprising only a monomer-derived repeating unit selected from L-lactic acid and D-lactic acid), L-lactic acid or D- A copolymer of lactic acid and a compound capable of copolymerization &quot;, or a mixture of both.

Of the polylactic acid-based polymers, polylactic acid is preferable, and a homopolymer of L-lactic acid (PLLA) or a homopolymer of D-lactic acid (PDLA) is most preferable.

The polylactic acid is a long-chain linked polymer obtained by polymerizing lactic acid by an ester bond.

The polylactic acid may be produced by a lactide method via lactide; A direct polymerization method in which lactic acid is heated under reduced pressure in a solvent and polymerization is carried out while removing water; And the like.

Examples of the polylactic acid include a homopolymer of L-lactic acid, a homopolymer of D-lactic acid, a block copolymer containing at least one polymer of L-lactic acid and D-lactic acid, and a polymer of at least one of L-lactic acid and D- And the like.

Examples of the compound copolymerizable with L-lactic acid or D-lactic acid include glycolic acid, dimethyl glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxypropanoic acid, Hydroxycaproic acid, 4-hydroxycaproic acid, 5- hydroxycaproic acid, 3-hydroxybutyric acid, 5-hydroxybutyric acid, Hydroxycarboxylic acids such as hydroxycaproic acid, 6-hydroxycaproic acid, 6-hydroxymethylcaproic acid, mandelic acid and the like; Cyclic esters such as glycolide,? -Methyl-? -Valerolactone,? -Valerolactone and? -Caprolactone; Polyvalent carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid and terephthalic acid, and anhydrides thereof; Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, Polyhydric alcohols such as 1,6-hexanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, tetramethylene glycol and 1,4-hexanedimethanol; Polysaccharides such as cellulose; aminocarboxylic acids such as? -amino acids; And the like.

Examples of the "copolymer of L-lactic acid or D-lactic acid and the compound copolymerizable with L-lactic acid or D-lactic acid" include block copolymers or graft copolymers having a polylactic acid sequence capable of generating spiral crystals have.

The concentration of the structure derived from the copolymer component in the helical chiral polymer (X) is preferably 20 mol% or less.

For example, when the helical chiral polymer (X) is a polylactic acid-based polymer, it is preferable that the molar ratio of the structure derived from lactic acid and the structure derived from a compound (copolymer component) copolymerizable with lactic acid in the polylactic acid- It is preferable that the concentration of the structure derived from the copolymer component is 20 mol% or less with respect to the total.

Examples of the polylactic acid-based polymer include a method in which the lactic acid described in JP-A-59-096123 and JP-A-7-033861 is directly dehydrated and condensed; Ring-opening polymerization using a cyclic excess chain lactide of lactic acid described in U.S. Patent Nos. 2,668,182 and 4,057,357; And the like.

In order to make the optical purity of the polylactic acid polymer obtained by each of the above-mentioned production methods 95.00% ee or more, for example, when polylactic acid is produced by the lactide method, the optical purity is 95.00% ee It is preferable to polymerize the lactide which has been improved to the above optical purity.

- Weight average molecular weight -

The weight average molecular weight (Mw) of the organic piezoelectric material is 50,000 to 1,000,000 as described above.

If the Mw of the organic piezoelectric material is 50,000 or more, the mechanical strength of the polymer film (A) is improved. The Mw is preferably 100,000 or more, more preferably 200,000 or more.

On the other hand, if the Mw of the organic piezoelectric material is less than 1,000,000, the moldability when the polymer film (A) is obtained by molding (for example, extrusion molding) is improved. The Mw is preferably 800,000 or less, more preferably 300,000 or less.

The molecular weight distribution (Mw / Mn) of the organic piezoelectric material is preferably 1.1 to 5, more preferably 1.2 to 4 in view of the strength of the polymer film (A). More preferably 1.4 to 3.

The weight average molecular weight Mw and the molecular weight distribution (Mw / Mn) of the organic piezoelectric material refer to values measured using a gel permeation chromatograph (GPC). Where Mn is the number average molecular weight of the organic piezoelectric material.

An example of a method for measuring Mw and Mw / Mn of an organic piezoelectric material by GPC is shown below.

- GPC measuring device -

GPC-100 manufactured by Waters

-column-

Shodex LF-804 manufactured by Showa Denko Co., Ltd.

- Preparation of sample -

A sample solution having a concentration of 1 mg / ml is prepared by dissolving the polymer film (A) in a solvent (for example, chloroform) at 40 占 폚.

-Measuring conditions-

0.1 ml of the sample solution is introduced into a column at a flow rate of 1 ml / min at a temperature of 40 ° C in a solvent [chloroform].

The sample concentration in the sample solution separated from the column is measured with a differential refractometer.

A universal calibration curve is prepared from a polystyrene standard sample and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the organic piezoelectric material are calculated.

The polylactic acid polymer which is an example of the organic piezoelectric material is a helical chiral polymer, and commercially available polylactic acid can be used.

Examples of commercially available products include PURASORB (PD, PL) manufactured by PURAC, LACEA (H-100, H-400) manufactured by Mitsui Chemicals, Inc., Ingeo ^TM biopolymer and the like.

When the polylactic acid polymer is used as the organic piezoelectric material, the polylactic acid polymer is preferably produced by a lactide method or a direct polymerization method in order to obtain a weight average molecular weight (Mw) of 50,000 or more of the polylactic acid polymer .

The polymer film (A) in the present disclosure may contain only one kind of the above-mentioned organic piezoelectric material, or two or more kinds thereof.

The content (the total content in the case of two or more kinds) of the organic piezoelectric material in the polymer film (A) is preferably 80% by mass or more based on the total amount of the polymer film (A). For example, when the organic piezoelectric material is a helical chiral polymer (X), the content of the helical chiral polymer (X) in the polymer film (A) (the total content in the case of two or more species) Is preferably 80% by mass or more.

[Stabilizer (Y)]

The polymer film (A) further includes a stabilizer (Y1) having one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group and an isocyanate group in a molecule and having a weight average molecular weight of 200 to 60000, And at least one stabilizer (Y) selected from the group consisting of a stabilizer having a non-ether group (Y2). As a result, the heat and humidity resistance of the polymer film (A) can be improved.

In the case where the polymer film (A) contains the stabilizer (Y), that is, the polymer film (A) contains at least one stabilizer (Y) selected from the group consisting of the stabilizer (Y1) and the stabilizer , The content of the stabilizer (Y) is preferably 0.01 parts by mass to 10 parts by mass, more preferably 0.01 parts by mass to 5 parts by mass, more preferably 0.1 parts by mass to 3 parts by mass relative to 100 parts by mass of the organic piezoelectric material More preferably 0.5 part by mass to 2 parts by mass. For example, when the organic piezoelectric material is a helical chiral polymer (X), the content of the stabilizer (Y) is preferably 0.01 parts by mass to 10 parts by mass relative to 100 parts by mass of the helical chiral polymer (X) More preferably from 0.1 part by mass to 3 parts by mass, and particularly preferably from 0.5 part by mass to 2 parts by mass.

When the content is 0.01 part by mass or more, the moisture resistance and heat resistance of the polymer film (A) is further improved.

When the content is 10 parts by mass or less, the lowering of transparency is further suppressed.

The above content represents the total amount of two or more stabilizing agents (Y) when they are used in combination.

(Stabilizer (Y1))

As the stabilizer (Y1), "stabilizer (B)" described in paragraphs 0039 to 0055 of International Publication No. 2013/054918 pamphlet can be used.

Examples of the compound (carbodiimide compound) having a carbodiimide group in one molecule which can be used as the stabilizer (Y1) include a monocarbodiimide compound, a polycarbodiimide compound and a cyclic carbodiimide compound.

As the monocarbodiimide compound, dicyclohexylcarbodiimide, bis-2,6-diisopropylphenylcarbodiimide and the like are preferable.

As the polycarbodiimide compound, those produced by various methods can be used. (Japanese Patent Publication No. 2941956, Japanese Patent Publication No. 47-33279, J. 0rg. Chem. 28, 2069-2075 (1963)), a method of producing a conventional polycarbodiimide [Chemical Review 1981, Vol.81 No.4, p619-621]) can be used. Specifically, the carbodiimide compound described in Japanese Patent No. 4084953 may be used.

Examples of the polycarbodiimide compound include poly (4,4'-dicyclohexylmethanecarbodiimide), poly (N, N'-di-2,6-diisopropylphenylcarbodiimide), poly , 5-triisopropylphenylene-2,4-carbodiimide), and the like.

The cyclic carbodiimide compound can be synthesized based on the method described in Japanese Patent Application Laid-Open No. 2011-256337.

As the carbodiimide compound, a commercially available product may be used. For example, a commercially available product such as B2756 (trade name), Nippon Chemical Co., Carbodilite LA-1, Rene Chemie, Stabaxol P, Stabaxol P400, Stabaxol I Trade name).

Examples of the compound (isocyanate compound) having an isocyanate group in one molecule which can be used as the stabilizer (Y1) include 3- (triethoxysilyl) propyl isocyanate, 2,4-tolylene diisocyanate, Diisocyanate, m-phenylenediisocyanate, p-phenylenediisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, Xylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and the like.

Examples of the compound (epoxy compound) containing an epoxy group in one molecule which can be used as the stabilizer (Y1) include phenyl glycidyl ether, diethylene glycol diglycidyl ether, bisphenol A-diglycidyl ether, Bisphenol A-diglycidyl ether, phenol novolak type epoxy resin, cresol novolak type epoxy resin, and epoxidized polybutadiene.

The weight average molecular weight of the stabilizer (Y1) is preferably 200 to 60000, more preferably 200 to 30,000, and still more preferably 300 to 18000 as described above.

If the molecular weight is within the above range, the stabilizer (Y1) is more likely to move and the moisture resistance of the polymer film (A) is improved.

The weight average molecular weight of the stabilizer (Y1) is particularly preferably 200 to 900. [ In addition, the weight average molecular weight of 200 to 900 almost coincides with the number average molecular weight of 200 to 900. In the case of a weight average molecular weight of 200 to 900, the molecular weight distribution may be 1.0. In this case, the &quot; weight average molecular weight 200 to 900 &quot; may be simply referred to as &quot; molecular weight 200 to 900 &quot;.

When the polymer film (A) contains the stabilizer (Y1), the polymer film (A) may contain only one type of stabilizer (Y1) or two or more types of the stabilizer (Y1).

As a preferred embodiment of the stabilizer (Y1), a stabilizer (Y1a) having at least one functional group selected from the group consisting of carbodiimide groups, epoxy groups and isocyanate groups and having a number average molecular weight of 200 to 900 and a carbodiimide (Y1b) having two or more functional groups selected from the group consisting of an epoxy group, an epoxy group and an isocyanate group in one molecule and having a weight average molecular weight of 1000 to 60000 are also used. The weight average molecular weight of the stabilizer (Y1a) having a number average molecular weight of 200 to 900 is approximately 200 to 900, and the number average molecular weight and the weight average molecular weight of the stabilizer (Y1a) are approximately the same value.

When the stabilizer (Y1a) and the stabilizer (Y1b) are used in combination as the stabilizer, it is preferable that the stabilizer (Y1a) is included in a large amount from the viewpoint of improvement of transparency.

Specifically, it is preferable that the stabilizer (Y1b) is in the range of 10 parts by mass to 150 parts by mass with respect to 100 parts by mass of the stabilizer (Y1a) from the viewpoint of compatibility between transparency and moist heat resistance, And more preferably in the range of the mass part.

Specific examples (stabilizers Y-1 to Y-3) of the stabilizer (Y1) are shown below.

Hereinafter, the above-mentioned stabilizers Y-1 to Y-3 are given the names of the compounds and commercial products.

ㆍ Stabilizer Y-1 ... The compound is bis-2,6-diisopropylphenylcarbodiimide. The weight average molecular weight (equivalent to a simple &quot; molecular weight &quot; in this example) is 363. Commercially available products include "Stabaxol I" manufactured by Rhein Chemie, and "B2756" manufactured by Tokyo Kasei Kasei.

ㆍ Stabilizer Y-2 ... The compound is poly (4,4'-dicyclohexylmethanecarbodiimide). As a commercially available product, "Carbodilite LA-1" manufactured by Nisshinbo Chemical Co., Ltd., having a weight-average molecular weight of about 2000, may be mentioned.

ㆍ Stabilizer Y-3 ... The compound is poly (1,3,5-triisopropylphenylene-2,4-carbodiimide). Commercially available products include "Stabaxol P" manufactured by Rhein Chemie, having a weight average molecular weight of about 3000. Further, "Stabaxol P400" manufactured by Rhein Chemicals Co., Ltd., having a weight average molecular weight of 20,000 can be mentioned.

(Stabilizer (Y2))

As the stabilizer (Y2) having an imino ether group, a compound (iminoether compound) containing an imino ether group in one molecule can be used. Examples of the imino ether compound include compounds represented by the following general formula (1).

R ² represents an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, an aryl group which may have a substituent or an alkoxy group which may have a substituent, and R ³ represents a group represented by the following general formula (2) R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent (s), or an aryl group represented by the following formula . R ² , R ³ , R ¹¹ , R ¹² and R ¹³ may be bonded to each other to form a ring. When R ³ is represented by the following general formula (2), the bond formed by at least one of R ¹¹ to R ¹³ and at least one of R ³¹ to R ³³ is a bond having two or more connecting atoms.

In the general formula (2), R ³¹ , R ³² and R ³³ each independently represent a hydrogen atom or a substituent. R ³¹ , R ³² and R ³³ may be connected to each other to form a ring. In the general formula (3), R ⁴¹ represents a substituent, and when a plurality of R ^{41 s} exist, they may be the same or different. N represents an integer of 0 to 5; In the formulas (2) and (3), * represents a position at which the compound bonds to the nitrogen atom.

In the general formula (1), the alkyl group represented by R ² is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms. The alkyl group represented by R ² may be straight chain or branched chain. The alkyl group represented by R &lt; ² &gt; may also be a cycloalkyl group. Examples of the alkyl group represented by R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert- , iso-pentyl group, n-hexyl group, sec-hexyl group, iso-hexyl group and cyclohexyl group. Among them, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an iso-butyl group and a cyclohexyl group are more preferable.

The alkyl group represented by R ² may further have a substituent. Examples of the substituent include an alkyl group, an aryl group, an alkoxy group, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group and an aldehyde group. The number of carbon atoms of the alkyl group represented by R ² represents the number of carbon atoms not containing a substituent.

The aryl group represented by R ² is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 12 carbon atoms. As the aryl group represented by R ² , a phenyl group, a naphthyl group and the like can be mentioned. Of these, a phenyl group is particularly preferable. The aryl group represented by R ² may further have a substituent. As the substituent, the above substituents can be exemplified. The carbon number of the aryl group represented by R ² represents the number of carbon atoms not containing a substituent.

The alkoxy group represented by R ² is preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, particularly preferably an alkoxy group having 2 to 6 carbon atoms. The alkoxy group represented by R ² may be straight chain, branched or cyclic. Preferable examples of the alkoxy group represented by R ² include a group in which -O- is connected to the terminal of the alkyl group represented by R ² . The alkoxy group represented by R ² may further have a substituent. As the substituent, the above substituents can be exemplified. The carbon number of the alkoxy group represented by R ² represents the number of carbon atoms not containing a substituent.

R ³ represents an alkyl group represented by the general formula (2) or an aryl group represented by the general formula (3). In the general formula (2), R ³¹ , R ³² and R ³³ each independently represent a hydrogen atom or a substituent. When R ³¹ , R ³² and R ³³ are substituents, they may be connected to form a ring. Examples of the substituent include an alkyl group, an aryl group, an alkoxy group, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group and an aldehyde group. R ³¹ , R ³² and R ³³ are all hydrogen atoms, or they may be the same or different substituents. The alkyl group represented by the general formula (2) may be linear or branched. The alkyl group represented by the general formula (2) may also be a cycloalkyl group.

In the general formula (3), R ⁴¹ represents a substituent and n represents an integer of 0 to 5. When n is 2 or more, R ⁴¹ may be the same or different. As the substituent, the above substituents can be exemplified. Further, n is more preferably 0 to 3, and still more preferably 0 to 2.

R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent. As the alkyl group and aryl group, the alkyl group and the aryl group which R ² can take are the same.

^{R 2, R 3, R 11} , R 12 and R ¹³ are preferably does not form a ring by combining to each other, ^{however, R 2, R 3, R} 11, R 12 and R ¹³ are bonded to form a ring . For example, when R ³ is represented by the general formula (3), at least one of R ⁴¹ and R ¹¹ to R ¹³ may be bonded to form a ring, or a benzene ring and any one of R ¹¹ to R ¹³ Containing ring may form a condensed ring. When R ³ is represented by the above general formula (3), it is preferable that at least one of R ⁴¹ and R ¹¹ to R ¹³ is not bonded to form a ring.

When R ³ is represented by the general formula (2), the bond formed by at least one of R ¹¹ to R ¹³ and at least one of R ³¹ to R ³³ is a bond having two or more connecting atoms. When R ³ is represented by the general formula (2), the bond formed by one of R ¹¹ to R ¹³ and one of R ³¹ to R ³³ is a bond having two or more connecting atoms, and is preferably a double bond. When R ³ is represented by the general formula (2), it is preferable that at least one of R ¹¹ to R ¹³ and at least one of R ³¹ to R ³³ are not bonded to form a ring.

The general formula (1) may contain a repeating unit. In this case, it is preferable that at least one of R ² , R ^3, or R ¹¹ to R ¹³ is a repeating unit, and the repeating unit includes an imino ether group.

The molecular weight of the stabilizer (Y2) per iminoether group is preferably 1000 or less, more preferably 750 or less, still more preferably 500 or less.

The molecular weight of the stabilizer (Y2), that is, the molecular weight of the entire iminoether compound is preferably 280 or more, and more preferably 300 or more.

When the polymer film (A) contains the stabilizer (Y2), the polymer film (A) may contain only one kind of the stabilizer (Y2) or two or more kinds of the stabilizer (Y2).

Further, for the compound represented by the general formula (1), reference can be made to the description in paragraphs 0015 to 0063 of International Publication No. 2015/194661 pamphlet.

[Other components]

The polymer film (A) may contain other components as necessary.

Other components include known resins such as polyethylene resin and polystyrene resin; Inorganic fillers such as silica, hydroxyapatite, and montmorillonite; A known nucleating agent such as phthalocyanine; Stabilizers other than stabilizers (Y); And the like.

As inorganic fillers and crystal nucleating agents, there may be mentioned the components described in paragraphs 0057 to 0058 of International Publication No. 2013/054918 pamphlet.

&Lt; Physical Properties of Polymer Film (A) >

[Standardized molecular orientation MORc]

The polymer film (A) according to the present disclosure has a normalized molecular orientation MORc of 1.0 to 15.0, preferably 2.0 to 15.0, more preferably 3.5 to 15.0, further preferably 3.5 to 10.0, and more preferably 4.0 to 8.0 Is more preferable.

The normalized molecular orientation MORc is a value determined based on the &quot; molecular orientation degree MOR &quot; which is an index indicating the degree of orientation of the organic piezoelectric material.

When the normalized molecular orientation MORc is in the range of 1.0 to 15.0, the strength of the film (polymer film (A)) is kept high, and the strength of the film in the specific direction (for example, The lowering of the strength of the film is suppressed.

When the MORc is in the range of 2.0 to 15.0, the number of molecular chains of the organic piezoelectric material arranged in the stretching direction is increased. As a result, when the polymer film (A) is used as a piezoelectric film, the generation rate of oriented crystals increases and it becomes possible to exhibit high piezoelectricity.

Here, the molecular orientation MOR (Molecular Orientation Ratio) is measured by the following microwave measurement method. That is, when the polymer film (A) is laminated in a microwave resonance waveguide of a well-known microwave transmission type molecular alignment system (also referred to as a microwave molecular orientation measuring apparatus) in such a manner that the surface (film surface) of the polymer film (A) Respectively. Then, the polymer film (A) is rotated in the plane perpendicular to the traveling direction of the microwave by 0 to 360 占 with the microwave whose direction of vibration is shifted in one direction continuously, and the intensity of the microwave transmitted through the sample is measured Thereby obtaining the molecular orientation MOR.

The normalized molecular orientation MORc is a molecular orientation degree MOR when the reference thickness tc is 50 m, and can be obtained by the following formula.

MORc = (tc / t) x (MOR-1) +1

(tc: reference thickness to be corrected, t: thickness of the polymer film (A)),

Standardized molecular alignment MORc can be measured at a resonance frequency of about 4 GHz or 12 GHz by a known molecular alignment system, for example, a microwave molecular alignment system MOA-2012A or MOA-6000 manufactured by Oji Keisoku Kiki Co.,

The normalized molecular orientation MORc can be controlled by, for example, heat treatment conditions (heating temperature and heating time) before stretching, stretching conditions (stretching temperature and stretching speed) and the like in the case where the polymer film (A) is a stretched film.

The normalized molecular orientation MORc can also be converted into a birefringence? N obtained by dividing the phase vehicle (retardation) by the film thickness. Specifically, the retardation can be measured using RETS100 manufactured by Otsuka Denshi Co., Ltd. Also, MORc and DELTA n are approximately in a linear proportional relationship, and when DELTA n is 0, MORc is 1. [

For example, when the organic piezoelectric material is a polylactic acid polymer and the birefringence? N of the polymer film (A) is measured at a measurement wavelength of 550 nm, when the normalized molecular orientation MORc is 2.0, the birefringence? N can be converted to 0.005 , And the normalized molecular orientation MORc is 4.0, the birefringence index can be converted into? N 0.01.

[Crystallinity]

The degree of crystallization of the polymer film (A) in the present disclosure is a value measured by the DSC method. The degree of crystallinity of the polymer film (A) in the present disclosure is 20% to 80%, preferably 20% to 70%, and more preferably 20% to 50%.

When the crystallinity is 20% or more, the strength of the film (polymer film (A)) is secured. When the degree of crystallinity is 80% or less, transparency of the film is kept high. Further, if the crystallinity is in the above-mentioned range, whitening or breakage hardly occurs when the film is stretched, so that it is easy to produce.

The polymer film (A) having a crystallinity of 20% or more is advantageous in that it improves heat resistance, but also improves the piezoelectricity (piezoelectric constant) when the polymer film (A) is used as a piezoelectric film.

[Product of normalized molecular orientation MORc and crystallinity]

In the polymer film (A) of the present disclosure, the product of the normalized molecular orientation MORc and the degree of crystallinity obtained by the DSC method when the reference thickness measured with the microwave transmission type molecular alignment system is 50 mu m is preferably 20 to 700, Is from 40 to 700, more preferably from 70 to 700, even more preferably from 75 to 680, even more preferably from 90 to 660, even more preferably from 100 to 650, still more preferably from 100 to 350. [

When the product of the normalized molecular orientation MORc and the degree of crystallinity obtained by the DSC method is in the range of 20 to 700, transparency and dimensional stability are suitably maintained.

When the product of the normalized molecular orientation MORc and the degree of crystallinity obtained by the DSC method is in the range of 40 to 700 (preferably 70 to 700), when the polymer film (A) is used as a piezoelectric film, maintain.

[Transparency (internal haze)]

The polymer film (A) in the present disclosure has an internal haze (hereinafter, simply referred to as "internal haze") of not more than 50%, preferably not more than 40%, more preferably not more than 20% More preferably 15% or less, still more preferably 13% or less, still more preferably 5% or less, still more preferably 1% or less. The inner haze of the polymer film (A) is preferably as low as possible from the viewpoint of transparency, and the lower limit is not particularly limited. However, the internal haze in the present disclosure can be 0.1% or more, for example.

The internal haze of 0.1% or more is suitable from the viewpoint of increasing the piezoelectric constant when the polymer film (A) is used as a piezoelectric film, for example.

In the present disclosure, "internal haze" refers to haze excluding haze due to the shape of the outer surface of the polymer film (A).

The term "internal haze" referred to herein is a value measured at 25 ° C. in accordance with JIS-K7105 for the polymer film (A).

Examples of the method of measuring the internal haze will be described later in Examples.

[Piezoelectric constant (stress-charge method)]

The polymer film (A) in the present disclosure is suitably used, for example, as a piezoelectric film.

When the polymer film (A) is used as a piezoelectric film, the piezoelectric constant of the polymer film (A) (piezoelectric film) refers to a value measured as follows.

First, the polymer film (A) was cut into 150 mm in a direction forming 45 degrees with respect to the stretching direction (e.g., the MD direction) of the polymer film (A) and 50 mm in a direction perpendicular to the direction making 45 DEG, . Subsequently, the obtained test piece is set on a test stand of SIP-600, Showa Shinku, and Al is deposited on one surface of the test piece so that the Al deposition thickness is about 50 nm. Subsequently, Al is similarly deposited on the other side of the test piece. As described above, a conductive layer of Al is formed on both surfaces of the test piece.

A test piece (polymer film (A)) of 150 mm x 50 mm in which a conductive layer of Al was formed on both surfaces of the polymer film (A) was stretched 120 mm in a direction forming 45 degrees with respect to the stretching direction (MD direction, for example) And cut out a rectangular film of 120 mm x 10 mm. This is used as a sample for measuring the piezoelectric constant.

The obtained sample is set on a tensile tester (manufactured by AND Co., Ltd., TENSILON RTG-1250) with a chuck distance of 70 mm so as not to be loosened. The crosshead speed is 5 mm / min, and the application force is periodically applied so as to reciprocate between 4N and 9N. At this time, in order to measure the amount of charge generated in the sample in accordance with the applied force, a capacitor of the capacitance Qm (F) is connected in parallel to the sample, and the inter-terminal voltage Vm of the capacitor Cm (95nF) is measured through the buffer amplifier . The generated charge quantity Q (C) is calculated as the product of the capacitor capacity Cm and the terminal voltage Vm. The piezoelectric constant d ₁₄ is calculated by the following equation.

d ₁₄ = (2 x t) / L x Cm? Vm /? F

t: sample thickness (m)

L: Distance between chucks (m)

Cm: Parallel connection capacitor capacity (F)

[Delta] Vm / [Delta] F: the ratio of change in voltage between the capacitor terminals

The higher the piezoelectric constant, the larger the displacement of the film relative to the voltage applied to the polymer film (A), and conversely the higher the voltage generated against the force applied to the polymer film (A) useful.

Specifically, the piezoelectric constant d ₁₄ measured by the stress-charge method at 25 캜 is preferably 1 pC / N or more, more preferably 3 pC / N or more, and even more preferably 4 pC / N or more. The upper limit of the piezoelectric constant is not particularly limited, but is preferably 50 pC / N or less, more preferably 30 pC / N or less in the polymer film (A) using an organic piezoelectric material from the viewpoint of balance of transparency and the like .

Also, from the viewpoint of balance with transparency, it is preferable that the piezoelectric constant d ₁₄ measured by the stress-charge method is 15 pC / N or less.

Here, the polymer film (A) of the present disclosure preferably has an internal haze of not more than 40% with respect to visible light and a piezoelectric constant d ₁₄ measured by a stress-charge method at 25 캜 of 1 pC / N or more . The preferable range of the internal haze for the visible light and the piezoelectric constant d ₁₄ measured at 25 캜 by the stress-charge method are as described above.

The polymer film (A) in the present disclosure may be a single layer film or a laminated film.

[thickness]

The thickness of the polymer film (A) in the present disclosure is not particularly limited, but may be, for example, 10 mu m to 1000 mu m, preferably 10 mu m to 400 mu m, more preferably 20 mu m to 200 mu m, More preferably from 20 탆 to 100 탆, and particularly preferably from 30 탆 to 80 탆.

However, in the case where the polymer film (A) is a laminated film composed of a plurality of layers, the thickness indicates the total thickness of the laminated film.

&Lt; Production method of polymer film (A)

The production method of the polymer film (A) in the present disclosure is not particularly limited. For example, a raw material of the polymer film (A) (an organic piezoelectric material such as a helical chiral polymer (X) such as a polylactic acid polymer ), And other components (stabilizer (Y), inorganic filler, etc.) as required, and extrusion-forming the mixture by a film-forming machine.

The production method for producing the piezoelectric film as the polymer film (A) is not particularly limited. For example, reference may be made to paragraphs 0065 to 0099 of International Publication No. 2013/054918 brochure as appropriate.

For example, as a preferable production method of the polymer film (A) (piezoelectric film), there are a first step of obtaining a pre-crystallized film containing a raw material of the polymer film (A), a first step of stretching in a uniaxial direction (Further comprising a step of carrying out an annealing treatment as occasion demands, including a second step of carrying out the above-mentioned annealing treatment).

Another preferred production method is a production method of a polymer film (A) comprising a step of primarily stretching a film containing a raw material of the polymer film (A) in a uniaxial direction and a step of performing an annealing treatment in this order .

&Lt; Protective Film (B) >

The laminate according to the present disclosure has a peelable protective film (B) in contact with one main surface of the polymer film (A).

As described above, the laminate according to the present disclosure may further include another peelable protective film in contact with the other main surface of the polymer film (A).

As the material of the protective film (B), for example, a polyolefin resin, a polyethylene terephthalate resin, a polyester resin (except for polyethylene terephthalate resin), a nylon resin, a polyvinyl alcohol resin, A resin, a polystyrene resin, a polyvinyl chloride resin, a polycarbonate resin, a polymethyl methacrylate resin, a polyurethane resin, a fluororesin, a polyacrylonitrile resin, a polybutene resin, a polyimide resin, Cellulose resin and the like.

These resins may be used singly or in combination of two or more kinds.

Of these resins, a polyolefin resin and a polyethylene terephthalate resin are preferable from the viewpoint of suppressing deterioration of the appearance of the polymer film (A) after the protective film (B) is peeled off. These resins may be used singly or in combination of two or more.

The protective film (B) may be a multilayer body of these resin layers.

Examples of the polyolefin-based resin include homopolymers of olefins, copolymers of two or more olefins, and copolymers of olefins and other monomers.

Examples of homopolymers of olefins include?-Polyolefin polymers such as polyethylene, polypropylene, polybutene and polymethylpentene; And cyclic polyolefin polymers. Examples of the two or more olefin copolymers include ethylene / propylene copolymer, propylene / ethylene / butylene copolymer, and ethylene-1-butene copolymer.

Examples of the polyethylene terephthalate resin include a polyethylene terephthalate resin produced by polycondensation of terephthalic acid and ethylene glycol, a polybutylene terephthalate resin produced by polycondensation of terephthalic acid and tetramethylene glycol, Polycyclohexanedimethylene terephthalate resin produced by polycondensation of cyclohexane dimethanol, polyethylene terephthalate resin produced by the air condensation of terephthalic acid, isophthalic acid and ethylene glycol, terephthalic acid and ethylene glycol and 1,4-cyclo A polyethylene terephthalate resin produced by the air condensation of hexane dimethanol, and a polyethylene terephthalate resin produced by the air condensation of terephthalic acid, isophthalic acid, ethylene glycol and propylene glycol. The polyethylene terephthalate resin may also contain structural units derived from other monomers.

[Base layer]

The protective film (B) preferably has a base layer and an adhesive layer formed on the main surface of the base layer opposite to the polymer film (A).

Examples of the material of the base layer include the same materials as those of the above-mentioned protective film (B). Among the resins, a polyolefin resin and a polyethylene terephthalate resin are preferable as the material of the base layer from the viewpoint of suppressing deterioration of the appearance of the polymer film (A) after the protective film (B) is peeled off. That is, the substrate layer is preferably made of a polyolefin resin or a polyethylene terephthalate resin.

These resins may be used singly or in combination of two or more.

The substrate layer may be a multilayer body of these resin layers.

[Adhesive layer]

As the material of the adhesive layer, there can be used, for example, an ethylene-vinyl acetate copolymer (EVA) -based adhesive, an acrylic adhesive, a rubber adhesive, a polyolefin adhesive (for example, a polyethylene oligomer adhesive), a cellulosic adhesive , A silicone type pressure sensitive adhesive, a urethane pressure sensitive adhesive, a vinyl alkyl ether pressure sensitive adhesive, a polyvinyl alcohol pressure sensitive adhesive, a polyvinyl pyrrolidone pressure sensitive adhesive, and a polyacrylamide pressure sensitive adhesive. Among them, an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive are preferred as the material of the pressure-sensitive adhesive layer from the viewpoint of suppressing deterioration of the appearance of the polymer film (A) after the protective film (B) is peeled off. In particular, the adhesive layer preferably includes an acrylic adhesive.

These pressure-sensitive adhesives may be used alone or in combination of two or more.

The adhesive layer may be a multilayer body.

An antistatic agent may be added to the adhesive layer in order to prevent peeling electrification.

Examples of the pressure-sensitive adhesive polymer of the acrylic pressure-sensitive adhesive include (meth) acrylic acid esters having an alkyl group of 1 to 10 carbon atoms such as 2-ethylhexyl acrylate, butyl acrylate, isooctyl acrylate, butyl methacrylate and propyl methacrylate, , A copolymer containing a functional group-containing unsaturated monomer such as methacrylic acid, maleic acid, fumaric acid, hydroxyethyl acrylate, and hydroxyethyl methacrylate.

Here, from the viewpoint of suppressing deterioration of the appearance of the polymer film (A) after the protective film (B) is peeled off, the laminate according to the present disclosure is characterized in that the base layer is made of a polyolefin resin or a polyethylene terephthalate resin, It is preferred that the layer comprises an acrylic adhesive.

[Acid value of adhesive layer]

The acid value of the adhesive layer is preferably 10 mgKOH / g or less, more preferably 0.01 mgKOH / g to 10 mgKOH / g, still more preferably 0.05 mgKOH / g to 5 mgKOH / g, more preferably 0.1 mgKOH / g to 1 mgKOH / g desirable.

If the acid value of the pressure-sensitive adhesive layer exceeds 0 mgKOH / g, the polar group of the pressure-sensitive adhesive layer interacts with the polar group of the polymer film (A), so that the adhesive strength between the pressure-sensitive adhesive layer and the polymer film (A) increases.

If the acid value of the pressure-sensitive adhesive layer is 10 mgKOH / g or less, the decrease in the molecular weight of the organic piezoelectric material contained in the polymer film (A) is suppressed and the stability of the polymer film (A) is improved.

In the laminate according to the present disclosure, the acid value of the adhesive layer indicates the amount (mg) of KOH required to neutralize the free acid in 1 g of the adhesive layer. The amount (mg) of KOH is measured by titrating the adhesive layer dissolved or swollen in a solvent with 0.005 M KOH (potassium hydroxide) ethanol solution using phenolphthalein as an indicator.

&Lt; Properties of protective film (B) >

[Maximum indentation depth hmax]

In the present disclosure, the maximum indentation depth hmax when the side of the protective film (B) that is in contact with the polymer film (A) is measured by the nanoindentation method is a value obtained by dividing the protective film (B) Is from 53 nm to 100 nm from the viewpoint of suppressing deterioration of the appearance of the resin (A). The measurement of the maximum indentation depth hmax by the nanoindentation method is performed in accordance with ISO 14577-1 (Instrumented indentation hardness). Details of the measurement method will be described in detail in Examples.

As described above, the maximum indentation depth hmax is 53 nm to 100 nm, but is preferably 53 nm or more and 80 mm or less, and more preferably 53 nm or more and 60 mm or less.

As the sample, a protective film (B) before (laminate) the main surface of the polymer film (A) may be used, or the protective film (B) after peeling the protective film (B) from the laminate may be used In either case, the maximum indentation depth hmax is measured on the side of the protective film (B) in contact with the polymer film (A).

When the protective film (B) has the base layer and the adhesive layer and the protective film (B) and the polymer film (A) are adhered via the adhesive layer, the maximum indentation depth hmax of the protective film (B) Is the maximum indentation depth when the side of the adhesive layer of the film (B) is measured. In this case, the maximum indentation depth hmax is regarded as the maximum indentation depth hmax of the adhesive layer.

[T-type peel strength]

In the present disclosure, the T type peel strength of the protective film (B) and the polymer film (A) is 0.07 N / 50 mm (A) from the viewpoint of suppressing deterioration of the appearance of the polymer film (A) More preferably 0.07 N / 50 mm to 0.5 N / 50 mm, and even more preferably 0.10 N / 50 mm to 0.3 N / 50 mm.

The "T-type peel strength" is a value measured at 25 ° C in accordance with JIS K6854-3 (1999) using a tensile tester (TENSILON RTG-1250, manufactured by AND Co.). Details of the measurement method will be described in detail in Examples.

[thickness]

The thickness of the protective film (B) is not particularly limited, but from the viewpoint of enhancing the protective function, the thickness is preferably in the range of 5 탆 or more, more preferably in the range of 10 탆 to 100 탆, Mu m, and particularly preferably in the range of 30 mu m to 50 mu m.

When the protective film (B) has a base layer and an adhesive layer, the thickness of the base layer is preferably in the range of 9 탆 to 99 탆, more preferably in the range of 19 탆 to 79 탆, Range is more preferable.

On the other hand, the thickness of the adhesive layer is preferably in the range of 1 탆 to 20 탆, more preferably in the range of 3 탆 to 10 탆.

The protective film (B) in the present disclosure may be a single-layer film, for example, a laminated film having a base layer and an adhesive layer as described above.

When the protective film (B) is a single-layer film, the protective film (B) is adhered to the polymer film (A) by, for example, adhesion or electrostatic attraction of the protective film (B) itself.

When the protective film (B) is a laminated film, the protective film (B) may have a functional layer.

Examples of the functional layer include an adhesive layer, a hard coating layer, an antistatic layer, an anti-blocking layer, a protective layer, an oligomer block layer and an electrode layer. These functional layers may be disposed on the main surface of the protective film B on the side opposite to the polymer film A or on the main surface opposite to the polymer film A of the protective film B, You can. The protective film (B) may have two or more functional layers.

In the laminate according to the present disclosure, it is preferable that the elastic modulus of the protective film (B) and the elastic modulus of the polymer film (A) satisfy the following relational expression (F).

The elastic modulus of the protective film (B) / the elastic modulus of the polymer film (A) (Formula F)

The polymer film containing an organic piezoelectric material having a protective film attached thereto may be stored for a long period of time in a roll state. The inventors of the present invention have found that a polymer film containing an organic piezoelectric material is stretched in one direction for imparting piezoelectricity, and therefore, when stored for a long period of time in a roll state, is slightly shrunk in the stretching direction and the film flatness is lowered. The lowering of planarity may further deteriorate the appearance and quality of a device manufactured using the polymer film.

However, when the ratio of the modulus of elasticity of the protective film (B) to the modulus of elasticity of the polymer film (A) is 0.1 or more as represented by the formula (F), the laminate relating to the present disclosure is stored The inventors of the present invention have found that, even when the protective film (B) is peeled off after the polymer film (A) is peeled off, the polymer film (A) is prevented from being shrunk and deformed.

In other words, by satisfying the above formula (F), even when the protective film is peeled off after a long-term storage in the roll state, the polymer film is not shrunk and deformed, and the planarity of the film can be maintained.

When the ratio of the modulus of elasticity of the protective film (B) to the modulus of elasticity of the polymer film (A) is 10 or less, the peeling point when the protective film (B) is peeled is stable and the appearance quality of the polymer film It becomes. Further, when the ratio of the modulus of elasticity of the protective film (B) to the modulus of elasticity of the polymer film (A) is 0.3 or more, the lowering of the planarity is more strongly suppressed.

Here, when the protective film (B) is a laminated film having a base layer and an adhesive layer, the modulus of elasticity of the protective film (B) in the formula (F) Is a composite elasticity modulus of elasticity.

In the present disclosure, the elastic modulus of each film means a value obtained by measuring the elastic modulus based on JIS K7127 (1999). Specifically, the modulus of elasticity is determined by cutting out a sample of 100 mm in the main stretching direction of the polymer film containing the organic piezoelectric material and 20 mm in the direction perpendicular to the main stretching direction of the polymer piezoelectric film with respect to the laminate, (1999), using a tensile tester (TENSILON RTG-1250 (trade name) manufactured by AND Co., Ltd.) for each of the polymer piezoelectric film and the protective film. Can be measured. The polymer film including the organic piezoelectric material may have anisotropy upon stretching, but in the present disclosure, the elastic modulus in the main stretching direction is measured.

From the viewpoint that the lowering of planarity is suppressed more strongly, it is preferable that in the laminate of the present disclosure, the protective film (B) is a laminated film having a base layer and an adhesive layer, the base layer is made of a polyethylene terephthalate- The adhesive layer preferably includes an acrylic adhesive.

By adopting such a constitution, the rigidity of the film becomes high. Therefore, even if the protective film (B) is peeled off after the laminate is stored in a roll for a long term of one year or longer, the deformation due to shrinkage of the polymer film (A) And the lowering of planarity is suppressed.

&Lt; Method of forming protective film (B) >

As a method of forming the protective film (B), a conventionally known known method can be appropriately used. For example, the protective film (B) can be formed by extrusion-forming the resin forming the protective film (B) by a film-forming machine.

In the case where the protective film (B) is a multilayer film comprising a plurality of layers including a base layer and an adhesive layer, for example, the formed base layer, the formed pressure-sensitive adhesive layer, and other layers Layer) may be adhered to form a multilayer film, or a multilayer film may be formed by extrusion-forming an adhesive layer and another layer on the formed base layer. Further, a multilayer film may be formed by co-extruding a material constituting the base layer and a material constituting the pressure-sensitive adhesive layer by a multi-layer film-forming machine. Further, an adhesive layer may be formed on the base layer by a wet coating method. In this case, a pressure-sensitive adhesive layer can be formed by applying a coating liquid (coating liquid for a pressure-sensitive adhesive layer) in which a material (resin, additive, etc.) for forming the pressure-sensitive adhesive layer is dispersed or dissolved.

From the viewpoint of improving the peeling property of the protective film (B), the surface of the protective film (B) may be treated by corona treatment, etch treatment, ozone treatment, plasma treatment or the like.

Examples of commercially available products of the protective film (B) include PAC series, JA series, KD series, MA series, NSA series, 622 series of Sekisui Kagaku Kogyo Co., Ltd.; FM series of Daio Kagoshima Kogyo Co., Ltd.; Sumiron's V series; E-MASK series of Nitto Denko Corporation; Mitsui Masking Tape of Mitsui Kagaku Tosell Corporation; Protect film series of Toyo Hoshi Co., Ltd.; Lintec Co., Ltd. industrial adhesive tape non-adhesive tape series; EM series of Higashiyama Film Co., Ltd.; And Prosave series of Kimoto Co., Ltd.

<Other protective film>

As described above, the laminate according to the present disclosure may further include another peelable protective film in contact with the other main surface of the polymer film (A).

When the laminate according to the present disclosure has another peelable protective film which is in contact with the other main surface of the polymer film (A), the same protective film as the protective film (B) can be used as the other protective film.

The other protective film and protective film (B) may be the same or different.

<First Aspect>

1 shows a cross-sectional view of a first embodiment of a laminate according to the present disclosure. The laminate (10) of the first embodiment has a polymer film (12) and a protective film (14). In the laminate 10 of the first embodiment, the protective film 14 is adhered to the polymer film 12 by the tackiness of the protective film 14 itself, or electrostatic attraction. Thereby, the surface of the polymer film 12 can be protected.

In the laminate 10 of the first embodiment, the maximum penetration depth hmax of the protective film 14 is adjusted to be in the range of 53 nm to 100 nm.

Therefore, according to the laminate 10 of the first embodiment, deterioration of the appearance of the polymer film 12 after the protective film 14 is peeled is suppressed.

<Second Aspect>

Fig. 2 shows a cross-sectional view of a second embodiment of the laminate according to the present disclosure. The laminate 10A of the second embodiment has the polymer film 12, the adhesive layer 16, and the base layer 18 in this order. In the layered product 10A of the second embodiment, the protective film 14A is composed of the adhesive layer 16 and the base layer 18. [ In the laminate 10A of the second embodiment, since the protective film 14A is adhered to the polymer film 12 via the adhesive layer 16, the protective film 14A and the polymer film 12, The adhesive force of the adhesive is increased.

Further, in the laminate 10A of the second embodiment, the maximum indentation depth hmax of the protective film 14A, that is, the maximum indentation depth hmax of the adhesive layer 16 is adjusted to be in the range of 53 nm to 100 nm.

Therefore, according to the layered product 10A of the second embodiment, deterioration of the appearance of the polymer film 12 after the protective film 14A is peeled is suppressed.

&Lt; Use of laminate >

When the laminate according to the present disclosure has a piezoelectric film having piezoelectricity (hereinafter referred to as &quot; piezoelectric film (A1) &quot;) as the polymer film (A), the protective film (B) The piezoelectric film A1 after the piezoelectric film A1 can be used as a piezoelectric film for a piezoelectric element such as a speaker, a headphone, a touch panel, an actuator, a remote controller, a microphone, an underwater microphone, an ultrasonic transducer, an ultrasonic applied instrument, a piezoelectric transducer, Accelerometer, shock sensor, vibration sensor, decompression sensor, tactile sensor, electric field sensor, sound pressure sensor, display, fan, pump, variable focus mirror, sound insulating material, soundproofing material, keyboard, sound device, information processor, measuring device, medical device And the like.

At this time, it is preferable that the piezoelectric film (A1) has at least two surfaces and is used as a piezoelectric element provided with electrodes on the surface. The electrodes may be provided on at least two surfaces of the piezoelectric film A1. The electrode is not particularly limited, and for example, ITO, ZnO, IZO (registered trademark), conductive polymer, or the like is used.

Further, the piezoelectric film (A1) and the electrode may be repeatedly used as stacked piezoelectric elements. As an example, the electrode and the unit of the piezoelectric film A1 are repeatedly overlapped, and finally the main surface of the piezoelectric film A1 not covered with the electrode is covered with the electrode. Concretely, the repetition of the unit is two times in the laminated piezoelectric element in which the electrode, the piezoelectric film (A1), the electrode, the piezoelectric film (A1) and the electrode are stacked in this order. The piezoelectric film (A1) used in the laminated piezoelectric element is one piezoelectric film (A1) of the piezoelectric film (A1) in the present disclosure, and the other layers are the piezoelectric film (A1) .

When the laminated piezoelectric element includes a plurality of piezoelectric films A1 and the organic piezoelectric material is the helix chiral polymer X, the optical properties of the helix chiral polymer X contained in the piezoelectric film A1, If the active polymer is active, the helical chiral polymer (X) contained in the piezoelectric film (A1) of the other layer may be L-shaped or D-shaped. The arrangement of the piezoelectric film (A1) can be appropriately adjusted in accordance with the use of the piezoelectric element.

For example, a first layer of a piezoelectric film (A1) containing an L-shaped helix chiral polymer (X) as a main component is bonded to a second layer containing an L-form helix chiral polymer (X) It is preferable that the uniaxial stretching direction (main stretching direction) of the first piezoelectric film A1 intersects with the uniaxial stretching direction (main stretching direction) of the second piezoelectric film A1 when the piezoelectric film A1 is laminated with the piezoelectric film A1, It is preferable that the directions of displacement of the first piezoelectric film A1 and the second piezoelectric film A1 are made coincident with each other and the piezoelectric properties of the laminated piezoelectric element as a whole become high.

On the other hand, the first layer of the piezoelectric film (A1) containing the L-shaped helix chiral polymer (X) as a main component is sandwiched between the second piezoelectric film (Main stretching direction) of the first piezoelectric film A1 is substantially parallel to the uniaxial stretching direction (main stretching direction) of the second piezoelectric film A1 when the first piezoelectric film A1 is laminated with the first piezoelectric film A1, It is possible to make the directions of displacement of the first piezoelectric film A1 and the second piezoelectric film A1 coincident with each other and to increase the piezoelectricity of the laminated piezoelectric element as a whole.

Particularly, when an electrode is provided on the main surface of the piezoelectric film (A1), it is preferable to provide an electrode having transparency. Here, the fact that the electrode has transparency means that the internal haze is 50% or less and the total light transmittance is 50% or more.

The piezoelectric device using the piezoelectric film A1 in the present disclosure can be applied to various piezoelectric devices described above such as a speaker and a touch panel. Particularly, a piezoelectric element having an electrode having transparency is suitable for application to a speaker, a touch panel, an actuator, and the like.

The piezoelectric element using the laminate according to the present disclosure can be applied to various piezoelectric devices described above such as a speaker and a touch panel. Particularly, a piezoelectric element having an electrode having transparency is suitable for application to a speaker, a touch panel, an actuator, and the like.

When the laminate according to the present disclosure has a polymer film (hereinafter referred to as &quot; polymer film (A2) &quot;) as the polymer film (A), the protective film (B) The polymer film A2 can be suitably used as an optical film or the like used in a display device or the like.

&Lt; Method for producing laminate >

The method for producing the laminate according to the present disclosure is not particularly limited, and for example, a polymer film (A) can be produced by the above-mentioned method, and the polymer film (A) can be produced by bonding with a protective film have.

The polymer film (A) and the protective film (B) may be produced by a known method or may be produced in advance.

<Examples>

Hereinafter, the embodiments of the present invention will be described in more detail with reference to examples, but the embodiments are not limited to the following examples unless the scope of the present disclosure is exceeded.

&Lt; Production of a polymer piezoelectric film &

As the organic piezoelectric material, a polylactic acid (trade name: Ingeo ^TM , manufactured by NatureWorks LLC, a helical chiral polymer (X) biopolymer, trade mark: 4032D). Then, 1.0 part by mass of Additive Z described later as a stabilizer (Y) was added to 100 parts by mass of the polylactic acid, followed by dry blending to prepare a raw material.

The prepared raw material was placed in an extruder hopper, extruded from a T die while being heated to 210 DEG C, and contacted with a cast roll at 50 DEG C for 0.3 minute to form a pre-crystallized sheet having a thickness of 150 mu m (preliminary crystallization step). The crystallinity of the pre-crystallized sheet was measured to be 6%.

The preliminarily crystallized sheet was heated at 70 占 폚 and stretched at a stretching speed of 10 m / min on a roll-to-roll basis, and uniaxially stretched to 3.5 times in the MD direction (stretching step).

Thereafter, the uniaxially stretched film was brought into contact with a roll heated at 145 占 폚 for 15 seconds in a roll-to-roll state and annealed to produce a polymer piezoelectric film as the polymer film (A) (annealing process step). The thickness of the obtained polymer piezoelectric film was 47.2 占 퐉.

- Additive Z-

As the additive Z, a mixture of Stabaxol P400 (10 parts by mass) manufactured by Rhein Chemie, Stabaxol I (70 parts by mass) manufactured by Rhein Chemie, and Carbodilate LA-1 (20 parts by mass) manufactured by Nisshinbo Chemical Co., Ltd. was used.

Details of each component in the mixture are as follows.

Stabaxol I: bis-2,6-diisopropylphenylcarbodiimide (molecular weight (= weight average molecular weight): 363)

Stabaxol P400: poly (1,3,5-triisopropylphenylene-2,4-carbodiimide) (weight average molecular weight: 20,000)

Carbodilate LA-1: Poly (4,4'-dicyclohexylmethanecarbodiimide) (weight average molecular weight: about 2000)

&Lt; Measurement of physical properties of polylactic acid &

The optical purity, weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polylactic acid contained in the polymer piezoelectric film were measured by the method described previously. The results are shown in Table 1.

&Lt; Measurement of Physical Properties of Polymer Piezoelectric Film &

The polymer piezoelectric film was measured for melting point Tm, crystallinity and internal haze by the following method. In addition, the piezoelectric constant d ₁₄ (stress-charge method) and the normalized molecular orientation MORc were measured by the method already described. The results are shown in Table 1.

[Melting point Tm and degree of crystallization]

The polymer piezoelectric film was precisely weighed in an amount of 10 mg and measured at a temperature raising rate of 10 캜 / min using a differential scanning calorimeter (DSC-1, manufactured by Perkin Elmer) to obtain a melting endothermic curve. From the obtained melting endothermic curve, melting point Tm and degree of crystallization were obtained. The results are shown in Table 1.

[Internal Hayes]

The internal haze (hereinafter also referred to as internal haze H1) of the polymer piezoelectric film was obtained by the following method. The results are shown in Table 1.

First, haze (H2) (%) was measured by sandwiching only silicon oil (Shin-Etsu Silicone (trademark) manufactured by Shin-Etsu Chemical Co., Ltd., model number: KF96-100CS) in advance between two glass plates. Then, the above-mentioned polymer piezoelectric film whose surface was uniformly coated with silicone oil was sandwiched between two glass plates, and the haze (H3) (%) was measured.

Subsequently, the internal haze (H1) (%) of the polymer piezoelectric film was obtained by taking the difference between them as shown in the following formula.

Internal Haze (H1) = Haze (H3) - Haze (H2)

Haze (H2) and haze (H3) (all units are%) were measured using the following apparatus under the following measurement conditions, respectively.

Measuring apparatus: manufactured by Tokyo Denshoku Co., Ltd., HAZE METER TC-HIIIDPK

Sample size: Width 30mm × length 30mm

Measurement conditions: According to JIS-K7136 (2000)

Measuring temperature: room temperature (25 캜)

&Lt; Example 1 >

A protective film (B) having a layer structure of a base layer (PET substrate) / adhesive layer (acrylic pressure-sensitive adhesive) as a protective film (B) was formed on the main surface of the polymer piezoelectric film produced by the above method using a laminator, (Thickness: 50 占 퐉) was laminated on the polymer piezoelectric film in the direction in which the main faces of the adhesive layer and the polymer piezoelectric film were opposed to each other to prepare a laminate having a layer structure of base layer / adhesive layer / polymer piezoelectric film. As the protective film, NSA33T manufactured by Sun Ai Kagaku Co., Ltd. was used.

<Characteristic measurement>

The maximum penetration depth hmax of the protective film, and the T type peel strength of the polymer piezoelectric film and the protective film were measured by the following methods.

[Maximum indentation depth hmax]

The protective film was peeled from the laminate produced in Example 1 and the side of the protective film that was in contact with the polymer piezoelectric film of the protective film was measured by the nanoindentation method, The depth hmax was measured.

More specifically, using a SPI3800 manufactured by SII as an AFM control unit, a TriboScope manufactured by Hysitron Corporation as a nanoindent module unit, and a Berkovich type (triangular abstraction: apex angle 142.3 deg.) Made of diamond as an indenter, The maximum indentation depth hmax was measured by press-fitting the indenter into a protective film under the condition of a maximum load of 10 占 에 by the load addition method.

The measurement was carried out at room temperature (25 占 폚) at 9 positions, and the average value of seven portions excluding the maximum value and the minimum value among the nine measured values was defined as the maximum indentation depth hmax of the protective film.

The measurement was carried out at room temperature (25 캜). The results are shown in Table 2.

[T-type peel strength]

After the laminate prepared in Example 1 was stored at room temperature for one month, a sample of 50 mm in the TD direction and 150 mm in the MD direction was cut out. The protective film and the polymer piezoelectric film were peeled 30 mm in the MD direction and set on a tensile tester (TENSILON RTG-1250 manufactured by AND Co.). The T-type peel strength of the polymer piezoelectric film and the protective film was measured according to JIS K6854-3 (1999) Respectively.

The measurement was carried out five times at room temperature (25 캜), and the average value thereof was taken as the T-type peel strength. The results are shown in Table 2. In Table 2, &quot; Tape Peel Strength of Large Piezoelectric Film &quot; indicates the T type peel strength.

[Modulus of elasticity]

A sample of 100 mm in the main stretching direction of the polymer piezoelectric film and 20 mm in the direction perpendicular to the main stretching direction of the polymer piezoelectric film was cut out of the laminate prepared in Example 1. The cut samples were peeled off with a polymer piezoelectric film and a protective film. Using a tensile tester (TENSILON RTG-1250 manufactured by AND Co.), each of the polymer piezoelectric film and the protective film was peeled off under the conditions of JIS K7127 1999). &Lt; / RTI &gt;

[Modulus of elasticity ratio]

The value of the ratio of the elastic modulus of the protective film / the elastic modulus of the polymer piezoelectric film was determined from the elastic modulus of the polymer piezoelectric film and the elastic modulus of the protective film obtained in the above measurement. The elastic modulus of the polymer piezoelectric film of Example 1 was 6.2 GPa.

<Evaluation>

[Evaluation of appearance after peeling of protective film (orange peel)] [

After the laminate prepared in Example 1 was stored at room temperature for one month, a sample of 300 mm in the TD direction and 300 mm in the MD direction was cut out. Subsequently, the protective film was peeled from the laminate, and then the appearance of the surface (adhesive surface with protective film) on which the protective film of the polymer piezoelectric film was laminated was judged by the following criteria.

-Evaluation standard-

A: No orange peel occurred at all

B: A little orange peel occurred.

C: Strong orange peel on the entire surface

[Evaluation of planarity after long-term storage]

After the laminate produced in Example 1 was stored at room temperature for one year, the protective film was peeled from the laminate. The polymer piezoelectric film was placed on a flat metal plate, and appearance was judged according to the following criteria.

-Evaluation standard-

A: Maintains planarity.

B: Partially non-planar

C: The entire surface is not planar.

In addition, the planarity observed in this evaluation is the flexure of the polymer piezoelectric film at 10 cm scale. Therefore, the evaluation of the planarity is an appearance evaluation which is different from the orange peel evaluation which is an evaluation of the irregularity of several mm scale.

&Lt; Example 2 >

The same operation as in Example 1 was carried out except that a protective film (JA13K made by Sun Ai Kagaku Co., Ltd., thickness: 35 mu m) having a layer structure of a base layer (polyolefin base) / adhesive layer (acrylic adhesive) was used as a protective film. The results are shown in Table 2.

&Lt; Example 3 >

The same operation as in Example 1 was carried out except that a protective film having a layer structure of a substrate layer (polyolefin substrate) / adhesive layer (acrylic pressure-sensitive adhesive) (KD23K manufactured by Sun Ai Kagaku Co., Ltd., thickness: 35 m) was used as the protective film. The results are shown in Table 2.

&Lt; Comparative Example 1 &

Except that a protective film (PAC-3-70 made by Sunei Kagaku Co., Ltd., thickness 70 mu m) having a layer structure of a substrate layer (LDPE substrate) / adhesive layer (EVA adhesive) was used as the protective film . The results are shown in Table 2.

&Lt; Comparative Example 2 &

Except that a protective film (PAC-3-50 THK made by Sun Ai Kagaku Co., Ltd., thickness 50 탆) having a layer structure of a substrate layer (LDPE substrate) / adhesive layer (special polyolefin adhesive) was used as the protective film . The results are shown in Table 2.

&Lt; Comparative Example 3 &

The same operation as in Example 1 was carried out except that a protective film (SPV-3643F manufactured by Nitto Denko Co., Ltd., thickness: 45 m) having a layer structure of base layer (polyethylene base) / adhesive layer (synthetic rubber adhesive) . The results are shown in Table 2.

- Explanation of Table 2 -

ㆍ PET represents polyethylene terephthalate.

ㆍ LDPE indicates low density polyethylene.

EVA represents an ethylene / vinyl acetate copolymer.

&Quot; 100 &quot; in Table 2 indicates that it is estimated that the maximum indentation depth hmax of the protective film exceeds 100 nm as described later.

As shown in Table 2, in Examples 1 to 3 using the protective film having the maximum indentation depth hmax in the range of 53 nm to 100 nm, it was found that the occurrence of orange peel was suppressed.

On the other hand, in Comparative Examples 1 and 2 using a protective film having a maximum indentation depth hmax of less than 53 nm, it was confirmed that orange peel occurred.

In Comparative Example 3, it was difficult to peel off the protective film, and the surface of the polymer piezoelectric film after peeling off the protective film became uneven. This is because the peeling strength between the protective film and the polymer piezoelectric film is excessively strong. From this result, in Comparative Example 3, it is estimated that the maximum penetration depth hmax of the protective film exceeds 100 nm.

Therefore, it was found that the deterioration of appearance (orange peel) of the polymer film after the protective film was peeled off was suppressed in the laminate of this example.

In addition, in Example 1 in which the modulus of elasticity ratio was 0.1 or more, the flatness of the polymer film after long-term storage was improved compared to Examples 2 and 3 in which the modulus of elasticity ratio was less than 0.1.

The disclosure of Japanese Patent Application No. 2016-046183 filed on March 9, 2016 is incorporated herein by reference in its entirety.

All publications, patent applications, and technical specifications described in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, and technical specification were specifically and individually indicated to be incorporated by reference.

10, 10A:
12: polymer film
14, 14A: protective film
16: Adhesive layer
18: Base layer

Claims (15)

Wherein the standardized molecular orientation MORc is 1.0 to 15.0 when the reference thickness measured with the microwave transmission type molecular alignment meter is 50 m and the crystallinity obtained by the DSC method is 20% To 80% and an internal haze with respect to visible light of not more than 50%
(B) which is in contact with one main surface of the polymer film (A)
And the maximum penetration depth hmax when the side of the protective film (B) contacting the polymer film (A) is measured by the nanoindentation method is 53 nm to 100 nm. The laminate according to claim 1, wherein the maximum indentation depth hmax is 53 nm to 60 nm. The optical film according to claim 1 or 2, wherein the protective film (B) has a base layer and an adhesive layer formed on the main surface of the base layer opposite to the polymer film (A)
And the maximum indentation depth hmax is a maximum indentation depth when the side of the adhesive layer of the protective film (B) is measured. The laminate according to claim 3, wherein the adhesive layer has an acid value of 10 mgKOH / g or less. The laminate according to claim 3 or 4, wherein the substrate layer is made of a polyolefin resin or a polyethylene terephthalate resin, and the pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive. The laminate according to any one of claims 1 to 5, wherein the T-shaped peel strength of the polymer film (A) and the protective film (B) is 0.07 N / 50 mm to 1 N / 50 mm. The polymer film (A) according to any one of claims 1 to 6, wherein the polymer film (A) has an internal haze of not more than 40% with respect to visible light and a piezoelectric constant d ₁₄ Is 1 pC / N or more. The laminate according to claim 7, wherein the internal haze is 1% or less. 9. The polymer film according to any one of claims 1 to 8, wherein the polymer film (A) has a normalized molecular orientation MORc of 3.5 to 15.0, a product of the normalized molecular orientation MORc and the crystallinity of 70 to 700, . The laminate according to any one of claims 1 to 9, wherein the organic piezoelectric material is a helical chiral polymer (X) having optical activity. The laminate according to claim 10, wherein the helical chiral polymer (X) is a polylactic acid polymer having a main chain containing a repeating unit represented by the following formula (1).

12. The laminate according to claim 10 or 11, wherein the helical chiral polymer (X) has an optical purity of 95.00% ee or more. The laminate according to any one of claims 10 to 12, wherein the content of the helical chiral polymer (X) in the polymer film (A) is 80 mass% or more. 14. The polymer film according to any one of claims 10 to 13, wherein the polymer film (A) has at least one functional group selected from the group consisting of a carbodiimide group, an epoxy group and an isocyanate group and has a weight average molecular weight of 200 to 60000 (Y) selected from the group consisting of a stabilizer (Y1) having an imino group and a stabilizer (Y2) having an imino ether group in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the helical chiral polymer (X) Mass part. The method according to any one of claims 1 to 14, wherein the modulus of elasticity of the protective film (B) and the modulus of elasticity of the polymer film (A)
The elastic modulus of the protective film (B) / the modulus of elasticity of the polymer film (A)
.

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